Well, maybe calling that safety stud by its right name will help clarify things. Winchester calls it the trigger stop, and its function is to block the trigger until the action is fully closed. It should do that, no matter when it contacts the lever. You shouldn't be able to pull the trigger unless you are gripping the lever firmly, unless someone has messed with the gun. In fact, there is a significant resistance from the trigger stop as the lever is fully closed.
How are you holding the lever when you fire the gun and the action opens? Are you holding it at all? How do you pull the trigger if the lever is not closed and you are not holding it? I don't know how you can get the rifle to fire with the lever other than all the way closed.